Gelable composition, resulting gelled polymer composition and use thereof

ABSTRACT

A fluid gelable composition, which sets autonomously to a waterswellable resilient solid, comprising: A. a sufficiently water-soluble salt of a selected, metal in a specified minimum amount; B. water in an amount sufficient to make 100 parts by weight of water and said salt; C. a selected water-dispersible synthetic polymer in an amount sufficient to yield a gel with said brine, said gel being as in ASTM D 555-58 and method of use of said composition to provide a fluidtight seal in underground passageways including the space between the exposed face of a geologic formation and a well casing, tunnel, shaft, or retaining wall.

United States Patent 72] Inventors Louis II. Eilers;

Christ F. Parks, Tulsa, Okla. [2]] Appl. No. 592,333 [22] Filed Nov. 7,1966 [45] Patented Jan. 12, 1971 [73] Assignee The Dow Chemical CompanyMidland, Mich. a corporation of Delaware [54] GELABLE COMPOSITION,RESULTING GELLED POLYMER COMPOSITION AND USE THEREOF 1 Claim, NoDrawings [52] U.S. Cl 166/295, 260/29.2, 260/296, 252/855 [51] Int. ClC09k 3/10, E2 1 b 3 3/00 [50] Field of Search 260/29.6HN, 29.60, 29.6M,29.6BM, 29.63, 29.2;

[5 6] References Cited UNITED STATES PATENTS 2,671,022 260/29.6(B)

3/ 1954 Sargent et al.

Primary Examiner-Murray Tillman Assistant Examinerwilbert J. Briggs, Sr.Attorneys-Griswold and Burdick and C. W. Carlin ABSTRACT: A fluidgelable composition, which sets autonomously to a water-swellableresilient solid, comprising:

(A) a sufficiently water-soluble salt of a selected metal in a specifiedminimum amount:

(B) water in an amount sufficient to make 100 parts by weight of waterand said salt:

(C) a selected water-dispersible synthetic polymer in an amountsufficient to yield a gel with said brine, said gel being as in ASTM D555-58 and method of use of said composition to provide a fluidtightseal in underground passageways including the space between the exposedface of a geologic formation and a well casing, tunnel, shaft, orretaining wall.

GELABLE COMPOSITION, RESULTING GELLED POLYMER COMPOSITION AND USETHEREOF The invention is an improved gelable composition and the methodof use thereof for sealing off openings against fluid flow.

In our copending application S.N. 371,665, filed June 1, 1964, anaqueous-based polyacrylamide sealant composition was described which canbe pumped into place as desired and which thereafter will gel to a hard,tough, resilient solid which is highly resistant to the passage offluids. Such composition consists essentially of an acrylamide polymerand an aqueous solution of an inorganic hydroxide or an inorganic salt,particularly a solution of both a divalent metal salt, e.g. CaC1 and apolyvalent (of a valence greater than two) metal salt, e.g. FeCl Thepresent invention has general application to sealing off a void orspace, against the entrance into or passage through, of encroachingwater and brines, which exists between the wall of a subterraneanformation and the casing or liner of a well shaft, tunnel, or otherexcavation penetrating or carved from a formation. It has specialapplication to large-diameter shafts extending into subterraneanformations including those comprising salt strata through whichpersonnel, equipment, and materials are raised and lowered. It is highlyeffective against the flow of aqueous solutions and dispersions becauseit swells upon contact by water.

The present invention is a method of closing off openings or.passageways, and composition required to be used therefor, consistingessentially of (A) an aqueous solution of a watersoluble monovalent orpolyvalent (including divalent) metal salt or mixture of such salts,which when admixed with pure water, as a test of suitability therefor,results in an aqueous tension (also known as the vapor pressure of waterand aqueous solutions) of less than 12 millimeters of mercury, (B)water, and C) a water-dispersible synthetic polymer, which will producea viscosity of at least about l centipoises when 1 percent by weight isadmixed with water at room temperature, illustrative of which arepolyvinyl alcohol, polyvinylpyrrolidone, polyvinylmorpholinone,polyvinyloxazolidinone, polyvinylalkyloxazolidinones, polyethyleneoxide, polyvinyltoluene sulfonate, polystyrene sulfonate, water-solublesalts of any of the above polymers, and polymers of maleic anhydridecopolymerized with any one of vinylmorpholinone, vinylpyrrolidone, vinylacetate, vinylbenzene sulfonate, or vinylbenzylsulfonate. Water-solublehalides, sulfates, acetates, formates, phosphates, and nitrates of Na,K, Li, NI-I.,, Ca, Mg, Sr,

Fe, Zn, Al. Sn. and Cu are illustrative of salts to use. Among suchsalts are CaCl- MgCl SrCl FeCl AlCl LiCl. KF, Nal. Kl. SnCL, CH COOK. CHCOONH4, Mg(NO;,)2. K CO Al (NO SnCl CuSO and mixtures and hydrates ofsuch salts.

A simple and acceptable test to employ to ascertain the desired amountof a polymer in a selected salt solution is determined by adding from 10to 75 grams of a selected polymer per 100 milliliters of salt solutionand choosing that amount of salt which yields a gel time of from 0.1 to48 hours at 80 or 150 F.

The gel time is that determined by the standard gel test designated ASTMD555-58, the gel time being taken as the lapse of time between admixtureof the polymer with the solution in a specified size and weight testtube and the time at which the gelation of the contents has progressedsufficiently to permit the test tube, together with the contents, to besuspended from a glass rod, which had been immersed therein prior togel, and then held in air suspended from the glass rod, in accordancewith said standard test as described in ASTM Standards 1958) Part 8,Sections and 51, page 263, under Gel Time of DryingOils.

Methods of preparing the polymers employed in the practice of theinvention are known. They are most commonly prepared by dissolving theselected monomer or mixture of monomers in an aqueous medium in thepresence of a freeradical polymerization catalyst, e.g. a peroxide or apersulfate, or by subjecting the monomeric mixture to irradiation, e.g.cobalt or high energy electrons which may be produced by a Vandergraafelectron accelerator.

Where a sulfonated polymer is desired, sulfonation is effectuated by theuse of such agents as I-I SO or S0 Where the sodium salt of a polymer isdesired, the polymer may be reacted with NaOI-I.

The following examples are illustrative of the practice of theinvention. Examples were conducted by preparing an aqueous salt solutionof a given concentration and admixing therewith the amount of previouslyprepared polymer stated in Tables I to VI, infra.

The gel time of each polymer-aqueous salt mixture was obtained accordingto ASTM D555-58, as previously described and recorded in hours intables. When certain of the sodium salt forms of the polymer wereemployed, e.g. sodium styrene sulfonate or the polymer containing themaleic anhydride half amide, there was present an excess of OH ionswhich necessitated addition of a small amount of hydrochloric acid tolower the pH value.

TABLE I Concentration Concentration ofgolymer Salt of salt in Gel in 1./gal. of Temperemployed weight percent time Example aqueous salt aturein in aqueous of aqueous salt in No. Polymer employed solution F.solution solution hours 1 Sodium polystyrene sullonate 3 B0 ZnClz 45 0.5 2-.. ..do 3 150 ZnClz 60' 0:1 3... Polyvinyl pyrrolldine. 6 80 ZnClz20' 2.0 4 .-do 5 150 ZnClz 60' 4:0 6..- Polyethyleneoxide 6 80 ZnClz0.05 6... Polyvinyl alcohol 3.5 ZnClz 60" 1. 0" 7. -d0 4 Z1101; '700.05. 8. Polyvinyl morpholinone- 3 80 211012 60- 0. 2.

9. d0 3 150 ZnClz 60 0:1 10 opolymer of vinylacetate, and maleicanhydride half amide 6 80 ZnClz 40 17. 0 11 do 3 150 ZnCI: 60 0.11

TABLE II Concentration Concentration of olyrner Salt salt in Gel inl./gal. of 'Iemperemployed weight percent time Exampl aqueous salt aturein in aqueous of aqueous salt 111' Polymer p y solution solutionsolution hours t 12 Sodium polystyrene sulfonate 5 80 C3012 40 24.0 13---do 5 150 CaCl; 40 1.5 14 Polyvinyl pyrrolidone. 6 80 C8012 20 2.0

5 150 CaClz 25 48.0

6 80 CaCIz 50 0.2

--- 6 150 CaCl: 50 0.1

6 80 CaCl2 20 0.5

TABLE III Concentration of polymer in Salt mixture Concentrationlb./gal. of employed in of salts in Gel Example aqueous saltTemperaaqueous salt weight percent time in No. Polymer employed solutionture in F. solution aqueous solution hours 24 Sodium polystyrenesullonate 5 80 C801: and 17.1 of each 48.

Z 01 (34.2 total). 25 d0 5 do 8.0 26.. Polyvinyl pyrrolidinone 6 027....... .do 6 1,2 28 Polyethylene oxide 6 0 1 29 o 6 0, 0 30..Polyvinyl alcohol. 4 0. 31.. .....d0 4 0.0 32 Copolymer of vinyl acetateand maleic anhydnde half amide 6 2.

33 ..do 6 o.... 0.1

TABLE IV Concentration of Salt Concentration of polymer in 1b.] employedin salt in weight Gel Example gal. of a ueous Temperaaqueous saltpercent of time No. Polymer employed salt so ution ture in F. solutionaqueous solution in hours 34 Sodium polystyrene sulionate 5 25 0 5 2 1236 Po yv nyl yrro one.. 3, 37 ..do.... 6 60 0. 5 3B Polyethylene oxide 560 18.0 39 -d 3 70 0. 1 40 Polyvinyl alcohol" 4 16 41 o 3. 6 70 24 42Polyvinvyl morpholinone 5 16 43 ..d0 5 60 2 44 Copolymer of vinylacetate and maleic anhydride half amide 5 20 48. 0 45 "do 6 25 14. 0

TABLE V Concentration of Salt Concentration 01 polymer in lb./ employedin salt in weight Gel Example gal. of aqueous Temperaaqueous saltpercent of time o. Polymer employed salt solution ture in F. solutionaqueous solution in hours 5 80 X20 0: 5. 0 5 150 K2003 70 0. 1 5 K200;60 8. 0 4 150 K: 70 4. 0 5 80 K2003 60 12. 0 4 KzCO; 70 0. 1 4 80 K2C0a40 0. 1 4 150 KzCOa 40 0. 05 5 80 K2003 30 24. 0 5 150 KzCCa 30 0. 2

TABLE VI Concentration of Salt Concentration of polymer in 1b.] employedin salt in weight Gel Example gal. of aqueous Tempereaqueous saltpercent of time No. Polymer employed salt solution ture in F. solutionaqueous solution in hours 56 Polyvinyl pyrrolidone 6 80 CaClz and 24. 2CaClz and 3. 0

FeCla. %.6 FeCla 57 0 6 150 Same Same; 0.1 58 Polyvinyl alcohol. 4 80-..do .3 0:101: and 0. 6

3.0 FeCl: (31.3). 59. ..do 4 150 do 37.7 CaClz and 0.16

als I 60 Copolymer of vinyl acetate and maleic anhydrlde halt amide 6 80..do l3i24ralzh and 12. 0

. e (14.6). 61 ..do 6 150 ....-do.. Same"-.. 0. 5

Reference to the examples set out in Tables I to VI shows that asatisfactory gel is obtained by the use of any of the variouscombinations of a polymer dispersed in the aqueous salt solutionsemployed in the examples. The Tables further show that the gel rate, ingeneral, is accelerated by a higher tem perature. and by certaingel-salt combinations, e.g. polyethylene oxide, polyvinyl alcohol, orpolyvinylmorpholinone with ZnCl or a mixture of ZnCl and CaCl or FeCland CaCl It shows, in general, that the gel rate is slower at a giventemperature and employing a selected polymer and salt at higher saltconcentrations.

It is suggested that preliminary test trials be conducted prior to alarge-scale plugging or sealing job, to ascertain the best combinationof polymer and salt and the concentrations thereof to produce a gelledplug within the desired time. Such tests can conveniently be conductedin a suitable small disposable container or vessel wherein thetemperature and time of gel are observed.

At higher temperatures, almost instantaneous gels can be obtained byemploying selected polymers and salts e.g, olyethylene oxide with ZnClor with mixtures of 2, and FeCl;,, or ZnCl 3): CaCl EXAMPLES 62 TO 65The purpose of these examples was to demonstrate the high tensilestrength of the gelled composition of the invention and its efficacy toplug off or provide a seal against fluid flow. The examples wereconducted by preparing aqueous salt dispersions of selected polymers,similarly, as in the examples of Tables l to V1, supra, employing theaqueous salt solution of the concentration shown in Table VII, infra,and the number of grams of polymer, per 100 milliliters of aqueous saltsolution, set out in Table VII.

Each fluid composition so made was placed in a 12-inch long, l-inchdiameter steel pipe at 76 F., where it gelled. After 24 hours, eachgelled composition in the pipe section was subjected to hydraulicpressure (water under measured pressure introduced into one end of thepipe against the gelled composition). The pressure at which the sointroduced water either moved past or through the gelled composition orcaused the gelled composition to move as a slug was recorded as theyield strength value of the composition.

The yield strength values of various compositions of the invention areset out in Table VII.

TABLE VII Aqueous salt solution in Yield Ex, percent by Polymer in gramsper 100 ml. of strength No. weight of salt aqueous salt solution inp.s.i.g.

62 35% C2101: 60 gms. sodium polystyrene 900 ull'onate. 63. 50% CaClg 75ms. polyethylene oxide 600 64". 60% ZnCl: 50 gms. polyvinyl aleohol 10065"... 35% ZIlClz 75 gms. vinyl pytrolidone maleic 500 anhydrideeopolymer.

Reference to Table VII shows the high yield strength values of thecomposition of the invention and its efficacy as a sealant or plugagainst the flow of water or aqueous solutions.

One embodiment of the invention encompasses flowing separate streams ofa nonaqueous dispersion of the polymer and of an aqueous solution of thesalt to the locus where the seal is desired. As the streams meet and mixby normal turbulence, gelation occurs either immediately or after adesired lapse of time.

Any water-dispersible synthetic polymer, prepared from a monomeric mixcontaining a vinyl-bearing monomer may be employed in the invention if a1 percent by weight solution thereof in water yields a viscosity of atleast about 10 centipoises. Between about 0.3 and 6.0 pounds of polymerper gallon of brine are preferred.

We claim:

1. The method of sealing an opening between the wall of a subterraneanformation and liner of a hole penetrating said formation, the linerbeing selected from the class consisting of well casings, shaft liners,excavations and mine shoring, retaining walls, foundations and footingsfor buildings, and tunnel liners, which method comprises:

A. emplacing in said opening a fluid gelable composition that setsautonomously to a water-swellable resilient solid which is highlyresistant to the passage of water and aqueous solutions and dispersionstherethrough said composition comprising: i l l. a water-soluble salt inan amount capable of lowering the vapor pressure of water to a value notgreater than about 12 millimeters of mercury and selected from the classconsisting of (a) halides of metals selected from the class consistingof Ca, Fe, Al and Zn and (b) acetates and carbonates of any of saidmetals and Li, K, Na, and NH, and hydrates and (0) mixtures of any ofsaid salts and hydrates;

2. water in sufficient amount to make parts by weight of brine with saidwater-soluble salt;

3. a selected water-dispersible synthetic polymer in an amountsufficient to provide between about 3 pounds and about 6 pounds ofpolymer per gallon of brine to yield a gel with said brine, said gelbeing defined by the standard test designated ASTM D555-58, saidsynthetic polymer being selected from the class consisting ofpolymerized homopolymers of sodium styrenesulfonate, vinylpyrrolidone,eth lene oxide, vmylmorpholmone, mixtures thereof, an copolymersconsisting of at least one monomer selected from the class above andvinyl acetate copolymerized with at least one other monomer selectedfrom the class consisting of maleic anhydride and maleic half amides,and B. maintaining said composition in place for a time sufficient forit to set so emplaced to said water-swellable resilient solid to providea seal against the passage of water and aqueous solutions through saidopening.

Pat t 255 4.28? Dated 1.2 Januarv 1Q'7l Inv n fls) Louis H. Eiler's andChrist F. Parks that error appears in the above-ideritifie'd patent Itis certified e hereby corrected as shown below:

and that said Letters Patent ar In column 5, line 22, delete "2" andinsert CaCl delete "3) 08.01" and insert and CaC1 in line 2 Signed andsealed this 11 th day of May 1971 (SEAL) Attest:

EDWARD M.FIETCHER,JR. Attesting Officer WILLIAM E. SGHUYLER, JCommissioner of Patent

2. water in sufficient amount to make 100 parts by weight of brine withsaid water-soluble salt;
 3. a selected water-dispersible syntheticpolymer in an amount sufficient to provide between about 3 pounds andabout 6 pounds of polymer per gallon of brine to yield a gel with saidbrine, said gel being defined by the standard test designated ASTMD555-58, said synthetic polymer being selected from the class consistingof polymerized homopolymers of sodium styrenesulfonate,vinylpyrrolidone, ethylene oxide, vinylmorpholinone, mixtures thereOf,and copolymers consisting of at least one monomer selected from theclass above and vinyl acetate copolymerized with at least one othermonomer selected from the class consisting of maleic anhydride andmaleic half amides, and B. maintaining said composition in place for atime sufficient for it to set so emplaced to said water-swellableresilient solid to provide a seal against the passage of water andaqueous solutions through said opening.